Thrombin is the key enzyme for coagulation and plays a central role in the pathology of venous and arterial thromboses, especially in view of its marked ability to cause auto-amplification of the coagulation cascade (F. Toti et al., Sang, Thrombose, Vaisseaux 1992, 4, 483-494 and T. M. Reilly et al., Blood Coagulation and Fibrinolysis 1992, 3, 513-517).
The direct and specific inhibition of thrombin is more efficient and poses fewer risks of haemorrhage than treatment with heparin. Direct inhibitors of thrombin currently exist but the disadvantage of those peptide substances is that they are not active when administered by the oral route.